1. Field of the Invention
The present invention relates to a rearview mirror assembly for motor vehicles, and more particularly to an automotive rearview mirror assembly which is capable of adjusting the angle of a rearview mirror mounted on an automobile door.
2. Description of the Relevant Art
Some automotive rearview mirror assemblies, particularly those mounted on automobile doors, are combined with a mechanism for adjusting the angle of the rearview mirror through a manually operated lever which projects into the passenger's compartment of the automobile.
FIG. 10 of the accompanying drawings schematically shows one conventional automotive rearview mirror assembly. As shown in FIG. 10, a remote control lever 101 projecting into a passenger's compartment is swingably mounted on a fixed vehicle body member 100, and a mirror housing 102 in which a mirror 103 is supported is mounted on the vehicle body outside of the passenger's compartment. The mirror 103 is pivotally supported within the housing 102 by a pivot 104 which has a stop 104a to prevent the mirror 103 from rotating within the housing 102. The mirror 103 is operatively coupled to the remote control lever 101 through a link mechanism 105. The link mechanism 105 comprises a first link 106, a shaft 107, and a second link 108. The first link 106 is connected between the remote control lever 101 and the shaft 107, which is rotatably and vertically movably supported in a sleeve 109 fixed to the housing 102. The second link 108, which is connected at one end to the shaft 107, has a distal end pivotally joined to the back of the mirror 103 at a position which is located obliquely upwardly of the pivot 104.
When the remote control lever 101 is swung back and forth in the longitudinal direction of the automobile (i.e., in directions normal to the sheet of FIG. 10), the first link 106 is angularly moved in a horizontal plane, causing the shaft 107 to rotate about its own axis within the sleeve 109. The rotation of the shaft 107 then rocks the second link 108 back and forth in the longitudinal direction of the automobile. When the second link 108 thus swings, the mirror 103 is tilted laterally about the pivot 104 for lateral angular adjustment thereof.
When the remote control lever 101 is swung vertically in the direction indicated by the arrow A or B, the shaft 107 is vertically moved in the sleeve 109 by the first link 106. The vertical movement of the shaft 107 is transmitted through the second link 108 to the mirror 103, which is then tilted vertically about the pivot 104 for vertical angular adjustment thereof.
As described above, vertical angular adjustments of the mirror 103 are achieved when the shaft 107 is vertically moved. However, since an extra space is necessary to allow the shaft 107 to move vertically therein, the mechanism for adjusting the angle of the mirror has an increased height, and the entire rearview mirror assembly is large in size. Therefore, limitations are imposed on the designing of the rearview mirror assembly.
There is a certain gap or clearance between the shaft 107 and the sleeve 109. Because the shaft 107 is subject to small lateral forces from the first link 106 when the shaft 107 moves vertically, the shaft 107 tends to move vertically in the sleeve 109 while the shaft 107 is being tilted with respect to the sleeve 109. As a consequence, the shaft 107 is held in localized abutment against the sleeve 109, and hence is subject to increased resistance when the shaft 107 moves vertically in the sleeve 109, with the result that increased forces are required to move the remote control lever 101. Such localized engagement between the shaft 107 and the sleeve 109 brings about localized wear on the shaft 107 and the sleeve 109 over a long period of time.
Another problem is that foreign matter such as dust particles is liable to be trapped between the shaft 107 and the sleeve 109 when the shaft 107 vertically moved in the sleeve 109. The deposited foreign matter between the shaft 107 and the sleeve 109 also increases the forces required to move the remote control lever 101.